Institute of Decision Science for a Sustainable Society, Kyushu University, Fukuoka 811-2415, Japan.
Graduate School of Human Science and Environment, University of Hyogo, Hyogo 670-0092, Japan.
Sci Rep. 2017 Feb 10;7:42102. doi: 10.1038/srep42102.
Dissolved organic matter (DOM) strongly affects water quality within boreal forest ecosystems. However, how the quality of DOM itself changes spatially is not well understood. In this study, to examine how the diversity of DOM molecules varies in water moving through a boreal forest, the number of DOM molecules in different water samples, i.e., rainwater, throughfall, soil water, groundwater, and stream water was determined using Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) in Norway spruce and Scots pine stands in eastern Finland during May and June 2010. The number of molecular compounds identified by FT-ICR MS (molecular diversity) ranged from 865 to 2,194, revealing large DOM molecular diversity in the water samples. Additionally, some of the molecular compounds were shared between different water samples. The DOM molecular diversity linearly correlated with the number of low-biodegradable molecules, such as, lignin-like molecules (lignins), but not with dissolved organic carbon concentration. The number of lignins shared between different sampling locations was larger than that of any other biomolecular class. Our results suggest that low-biodegradable molecules, especially lignins, regulate spatial variations in DOM molecular diversity in boreal forests.
溶解有机质（DOM）强烈影响北方森林生态系统的水质。然而，DOM 本身的质量如何在空间上发生变化还不是很清楚。在这项研究中，为了研究 DOM 分子的多样性如何在流经北方森林的水中发生变化，使用傅里叶变换离子回旋共振质谱（FT-ICR MS）在 2010 年 5 月和 6 月，在芬兰东部的挪威云杉和苏格兰松林中的不同水样（即雨水、穿透雨、土壤水、地下水和溪流水）中测定了不同水样中 DOM 分子的数量。FT-ICR MS 鉴定的分子化合物数量（分子多样性）范围为 865 至 2194，表明水样中存在大量 DOM 分子多样性。此外，一些分子化合物在不同的水样之间是共有的。DOM 分子多样性与低生物降解性分子（如木质素样分子（木质素））的数量呈线性相关，但与溶解有机碳浓度无关。不同采样点之间共有的木质素数量大于任何其他生物分子类别的数量。我们的结果表明，低生物降解性分子，特别是木质素，调节北方森林中 DOM 分子多样性的空间变化。
